Rat Bladders Augmented with a Novel Bovine Pericardium‐Derived Biomaterial Reconstruct Functional Tissue Structures

Objectives: To determine if rat bladders augmented with an acellular Japanese bovine pericardium‐derived biomaterial (CardioDISC [CD]) could support bladder reconstruction, and increase bladder volume and compliance. Methods: Female Sprague–Dawley rats were randomly divided into three groups ( n = 5 each). After partial cystectomy, bladders were closed without augmentation (non‐augmentation) or augmented with porcine small intestinal submucosa (SIS) or CD, both of which are acellular. At 1, 2, 4 and 8 weeks after surgery, bladder volume and compliance were measured. The bladders were then analyzed by immunohistochemistry for smooth muscle actin (SMA), urothelium uroplakin III (UPIII), and nerve fiber S100. Results: At 4 weeks after augmentation, the SMA‐positive cells from the host bladder tissues were present near the regions augmented with CD. In addition, S100‐positive cells were present within the CD‐augmented tissues. At 8 weeks after surgery, the CD‐augmented tissues contained layered SMA‐positive cells, urothelium uroplakin III ‐positive urothelium, and S100 fibers, similar to normal bladder tissue. The SIS‐augmented bladders showed similar results. At 8 weeks after augmentation, the bladder volume of CD‐augmented bladders was larger than that at 4 weeks, while the SIS‐augmented bladders were the same as those at 4 weeks. The bladder volume of the non‐augmented group did not increase. The bladder compliance of the CD‐augmented bladders at 8 weeks was significantly higher than at earlier times. The bladder compliance of neither the non‐augmented nor the SIS‐augmented groups increased during the study period. Conclusion: Acellular bovine pericardium‐derived material could be a suitable biomaterial for bladder augmentations